Product vs. demand analysis

[mipo]

Hello,

Hope you're well.

I have a long list of products which expire in a certain month in the future. These products might repeat themselves as the expiration date of the same product might be in different months in the future. If the same product has several expiration months it has it's own row in excel. I also have a list of product demand which inform of the quantities to be consumed in each month in the future. When I do a vlookup of demand to the product list I have, the same demand quantity for the same products appear even if the product expires in a different month. This is not true as the demand volumes are duplicated for the same products and does not take into consideration the already consumed quantity in prior months. How to make a formula or a pivot table in excel which would inform of any leftovers of products as there will not be enough demand to consume it up to the product’s expiration month while taking into consideration the already covered demand by product quantity in prior expiration months of the same products listed in a different row?

Please find attached an example.


Thank you for your time and consideration.

Michal